This project is concerned with the ontogeny of perceptual analysis and selective attention. Specifically, it is assumed that younger children perceive complex stimuli wholistically and do not, therefore, attend selectively to the component dimensions of the stimulus. Further, with increasing perceptual experience, the child is assumed to analyze stimuli into dimensions but to fail in focusing attention. In order to evaluate these questions, a variety of tasks are used, including multidimensional scaling, free and speeded classification, discrete trial reaction time, and redundant relevent cues learning. By converging on the ontogeny of perceived structure and attention, it will be possible not only to identify their properties, but to predict age-related differences in tasks that this research does not currently employ. BIBLIOGRAPHIC REFERENCES: Kemler, D. G.,Shepp, B. E., and Foote, K. E. The sources of developmental differences in children's incidental processing during discrimination trails. Journal of Experimental Child Psychology, 1976, 21, 226-240. Shepp, B. E. and Swartz, K. B. Selective attention and the processing of integral and nonintegral dimensions: A developmental study. Journal of Child Psychology, 1976, 22, 73-85.